<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Dom is Ready</title>
    <script src="js/underscore-min.js"></script>
    <script>
        let a = {
            name: 'yangkai',
        };
        let b = {
            name: 'yangkai',
        }
        console.log(a === b);
        console.log(_.isEqual(a, b));
        for (let i = 0; i < 1000000000; i++) {} // 这段同步脚本将会延迟DOM解析,
        // 所以DOMContentLoaded事件将会延迟执行.
        document.addEventListener('DOMContentLoaded', function () {
            document.querySelector('footer').style.backgroundColor = 'purple';
        });

    </script>
</head>

<body>
    <footer>你好</footer>
</body>

</html>